Intake-valve-free compressor

ABSTRACT

A compressor cylinder is provided, along its outer periphery, with an annular supply channel for a working fluid, this channel communicating with the interior of the cylinder via a multiplicity of triangular ports lying in the path of reciprocation of the piston. The cylinder head carries an outlet with a check valve which closes during the suction stroke so that a partial vacuum is created inside the cylinder until the piston clears the ports to aspirate the fluid; upon the subsequent return stroke, the fluid is discharged through the outlet past the check valve.

United States, Patent [1 1 Chomczyk et al.

[ Jan. 29, 1974 3,065,701 11/1962 Bessiere 417/245 2,985,358 5/1961 Lee et a1 417/490 2,812,893 11/1957 Cotter 417/493 1,342,273 6/1920 Blache 92/153 1,486,651 3/1924 Freundlich.... 417/501 1,002,760 9/1911 Rix 417/495 Primary Examiner-William L. Freeh Attorney, Agent, or Firm--Karl F. Ross ABSTRACT A compressor cylinder is provided, along its outer periphery, with an annular supply channel for a working fluid, this channel communicating with the interior of the cylinder via a multiplicity of triangular ports lying in the path of reciprocation of the piston. The cylinder head carries an outlet with a check valve which closes during the suction stroke so that a partial vacuum is created inside the cylinder until the piston clears the ports to aspirate the fluid; upon the subsequent return stroke, the fluid is discharged through the outlet past the check valve.

1 Claim, 1 Drawing Figure INTAKE-VALVE-FREE COMPRESSOR CROSS REFERENCE TO RELATED APPLICATIONS This is a continuation-in-part of our copending application Ser. No. 877,963 filed on November 19, I969.

FIELD OF THE INVENTION Our present invention relates to a compressor having a port-and-valve system adapted to eliminate the need for an intake or induction valve.

BACKGROUND OF THE INVENTION Reciprocating-piston compressors have hitherto been provided with timing system of two distinct types. In one type, mechanical or hydraulic means closely couples the movement of the piston with the valve. In the other system the opening of the valves is accomplished by the pressure in the cylinder upon reciprocation of the piston. These systems have been found to be noisy, bulky, of limited speed and defective particularly with respect to the suction valve.

OBJECT OF THE INVENTION It is the principal object of the invention to provide an improved compressor system whereby the aforementioned disadvantages can be obviated.

SUMMARY OF THE INVENTION This object can be attained, in accordance with the present invention, which provides a compressor for a working fluid having a cylinder with an open end and a closed end, the closed end being formed with an outlet in which a check valve is provided for preventing induction of fluid. The compressor has no induction or intake valve and comprises a piston extending into the cylinder by the open end as well as drive means for reciprocating the piston toward and away from the closed end so that the piston has a dead-center position remote from the closed end. A valveless annular channel surrounds the cylinder and communicates with the interior thereof by a multiplicity of peripherally spaced inlet ports formed in the cylinder and alternately cut off and uncovered by the piston during each reciprocating stroke thereof, thereby connecting the interior of the cylinder with the channel only as the piston nears its dead-center position mentioned earlier. The inlet ports are spaced above the dead-center position toward the closed end. A valveless supply conduit for the working fluid terminates at the channel and a filter can be provided in the supply conduit.

The compressor according to a further feature of the present invention has a stroke which is substantially equal to the piston length so that the inlet orifices remain covered by the piston as it rises and compresses the fluid in the chamber. The bore of the cylinder is about one-fifth larger than its stroke, so that the compression rate is rapid and efficient.

In accordance with yet another feature of this invention the inlet orifices are substantially triangular in shape with their apexes directed longitudinally in the cylinder toward the dead-center position of the piston. In this manner, on retraction of the piston during intake, the piston pulls first beyond the bases of these triangular suddenly exposing a maximum area the intake orifices. Thereafter, since the pressure differential is less, the ratio of intake area uncovered to piston displacement decreases to zero.

In prior-art devices square intake orifices were frequently provided which created a disadvantage intake. Even round holes, although slightly better, failed to allow the pressure in the intake manifold to fall off smoothly, a fact that made it impossible to use a filter on the intake since the intake subjected the filter to two pressure waves, whereas in the present invention only one such shock is created to save the filter from the second shock.

In addition, according to yet another feature of this invention the intake orifices have an overall surface area which is equal to about one third of the surface area of the piston. These orifices are also spaces above the dead-center or bottom position of the piston by a distance equal to about 15 percent of the piston stroke to ensure that the cylinder is at atmospheric pressure when the piston rises and starts blocking off these intake ports again.

DESCRIPTION OF THE DRAWING The above and other objects, features and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which the sole FIGURE is an axial cross-sectional view, partly in diagrammatic form, of a compressor embodying the invention.

SPECIFIC DESCRIPTION In the drawing we have shown a compressor in which the cylinder 2 is provided with a row of 14 triangular ports 1 spaced above the dead-center position of the piston 3 which is shown slightly above its dead-center position. The ports 1 are closed and opened by the piston 3 which is reciprocated by the crankshaft represented at 6 and the connecting rod 5. The crankshaft is driven by an electric motor 14.

A channel 7 surrounds the cylinder 2 and communicates with the ports 1 via a valveless intake duct provided with a filter 8.

At the closed end or cylinder head 10, a check valve 9 is provided.

When the piston is moved downwardly, it creates a vacuum in cylinder 2. As the upper edge of the first ring of the sealing rings 12 and the scraper ring 13 clears the upper edge of ports 1, the cylinder 2 is charged with the medium from the channel 7. The rate at which the fluid enters through the ports 1 is, of course, a function of the pressure differential between the interior of compression chamber 11 and the exterior and is produced by the movement of the piston into its lower deadcenter position past the ports. The time between unblocking of the ports 1 and to the moment at which the piston is shifted upwardly to again close the ports, should be greater than the time required for equalizing the pressure, i.e., charging the cylinder with the medium to be compressed.

The upward movement of the piston thus compresses the fluid in chamber 11 and, when the pressure is sufficient, opens valve 9 to discharge the medium into a pressure vessel or pneumatic system. Apart from the blocking and unblocking of the ports 1, the piston rings 12 also serve to seal the compression space 11 while scaper or lubricating ring 13 scrapes lubricant from the cylinder 2 and prevents penetration of lubricant into the intake ports 1.

The triangular ports 1 are isosceles and have a width a which is around two-thirds of their height h and each have and overall area equal to around one-fortieth of the area of the top of the piston 4. The chamber 11 has a bore D which is around 20 percent larger than the length C of the piston 4, which in turn is substantially equal to the stroke E of this piston.

The intake manifold 7 is substantially rectangular in cross section with a width 3 slightly smaller, by onesixth, than its height h, giving it a volumetric capacity which is equal to substantially two-fifths that of the cylinder 11. The intake tube from the filter 8 has a height and width i equal to the height h.

Since the bases of the triangular ports 1 all lie in a common plane P orthogonal to the reciprocation axis A of the piston 4, they will all be covered up at the same instant on rising of the piston, and all will be similarly uncovered in an instant on descent. The aspexes of these triangular ports 1 are directed toward the open end of the cylinder 2 so the filter 8 will only be subjected to a single pressure shook as the piston 4 either covers or uncovers these ports 1. They remain'covered by the piston since the piston length C is substantially equal to its length C. In addition the lowerscraper ring 13 is spaced above the bottom of the piston 4 by a distance k substantially equal to the distance f so that once the piston 4 has passed the plane P during its compression stroke, these ports 1 will remain blocked until the piston 4 descends to the plane P during the intake stroke. In this manner the pressure in the intake manifold 7 can equalize and the filter 8 is not subjected to the buffeting of any unproductive intake or exhaust steps as is common in prior-art systems.

We claim:

1. An induction-valve-free compressor for a workingfluid, comprising:

a cylinder with an open end and a closed end, said closed end being provided with an outlet;

a check valve in said outlet adapted to permit said fluid to escape from said cylinder;

a piston extending into said cylinder and reciprocable between a dead-center position near said open end and a compression position at said closed end;

a valveless annular channel surrounding said cylinder and communicating with the interior of said cylinder througha plurality of peripherally spaced isosceles-triangular ports formed in the cylinder and spaced above said dead-center position toward said closed end, said ports having bases lying in a common plane orthogonal to the reciprocationaxisof said piston and having apexes directed toward said open end;

means for reciprocating said piston between said positions and thereby alternately uncovering said ports to permit fluid flow between said channel and the interior of said cylinder and covering said ports;

a valveless supply conduit for said working fluid terminating at said channel;

a filter in said supply conduit; and

at least two axially spaced sealing rings on said piston engaging said cylinder, the ring toward said open end being spaced from the end of said piston turned toward said open end by a distance substantially equal to the distance between the apexes of said ports and the other end of said piston in said dead-center position thereof, said ports having a combined area equal to substantially one-third the area of said other end of said piston. 

1. An induction-valve-free compressor for a working fluid, comprising: a cylinder with an open end and a closed end, said closed end being provided with an outlet; a check valve in said outlet adapted to permit said fluid to escape from said cylinder; a piston extending into said cylinder and reciprocable between a dead-center position near said open end and a compression position at said closed end; a valveless annular channel surrounding said cylinder and communicating with the interior of said cylinder through a plurality of peripherally spaced isosceles-triangular ports formed in the cylinder and spaced above said dead-center position toward said closed end, said ports having bases lying in a common plane orthogonal to the reciprocation axis of said piston and having apexes directed toward said open end; means for reciprocating said piston between said positions and thereby alternately uncovering said ports to permit fluid flow between said channel and the interior of said cylinder and covering said ports; a valveless supply conduit for said working fluid terminating at said channel; a filter in said supply conduit; and at least two axially spaced sealing rings on said piston engaging said cylinder, the ring toward said open end being spaced from the end of said piston turned toward said open end by a distance substantially equal to the distance between the apexes of said ports and the other end of said piston in said dead-center position thereof, said ports having a combined area equal to substantially one-third the area of said other end of said piston. 